Meeting Abstract
Small-scale shifts in population distributions are expected to occur in the intertidal zone under future climate scenarios and may reduce fitness. The intertidal crab, Petrolisthes cinctipes, experiences thermal fluctuations that can reach lethal levels. However, both the extent to which crabs move in response to temperature and the thermal thresholds that trigger migration to cooler microhabitats remain unknown. Escape reflexes, which vary with size and reproductive state, allow organisms to remain within their preferred habitat where they are near their optimal body temperature. Smaller crabs have a higher escape temperature (Tesc) (R2=0.39, p<0.01) compared to larger ones. Gravid females have a lower mean Tesc (19.6°C) than non-gravid crabs (22.1°C). Behavioral responses to changes in temperature may be controlled by thermosensory neuronal systems in the walking legs, as whole organism and neural thermal tolerance are correlated with habitat temperature. We aim to define the thermal thresholds that elicit avoidance behavior, determine variance in populations, and elucidate the mechanical cause by comparing spontaneous action potentials to Tesc during stress. The vulnerability of marine organisms to global change is predicated on their ability to utilize and integrate these physiological and behavioral strategies to promote survival and reproductive fitness; understanding these strategies will allow predictions of species distributions under warming and the potential for local extinction.
